golang-image/bmp/reader_test.go

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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bmp
import (
"fmt"
"image"
"os"
"testing"
_ "image/png"
)
const testdataDir = "../testdata/"
func compare(t *testing.T, img0, img1 image.Image) error {
b := img1.Bounds()
if !b.Eq(img0.Bounds()) {
return fmt.Errorf("wrong image size: want %s, got %s", img0.Bounds(), b)
}
for y := b.Min.Y; y < b.Max.Y; y++ {
for x := b.Min.X; x < b.Max.X; x++ {
c0 := img0.At(x, y)
c1 := img1.At(x, y)
r0, g0, b0, a0 := c0.RGBA()
r1, g1, b1, a1 := c1.RGBA()
if r0 != r1 || g0 != g1 || b0 != b1 || a0 != a1 {
return fmt.Errorf("pixel at (%d, %d) has wrong color: want %v, got %v", x, y, c0, c1)
}
}
}
return nil
}
// TestDecode tests that decoding a PNG image and a BMP image result in the
// same pixel data.
func TestDecode(t *testing.T) {
testCases := []string{
"video-001",
"yellow_rose-small",
}
for _, tc := range testCases {
f0, err := os.Open(testdataDir + tc + ".png")
if err != nil {
t.Errorf("%s: Open PNG: %v", tc, err)
continue
}
defer f0.Close()
img0, _, err := image.Decode(f0)
if err != nil {
t.Errorf("%s: Decode PNG: %v", tc, err)
continue
}
f1, err := os.Open(testdataDir + tc + ".bmp")
if err != nil {
t.Errorf("%s: Open BMP: %v", tc, err)
continue
}
defer f1.Close()
img1, _, err := image.Decode(f1)
if err != nil {
t.Errorf("%s: Decode BMP: %v", tc, err)
continue
}
if err := compare(t, img0, img1); err != nil {
t.Errorf("%s: %v", tc, err)
continue
}
}
}